Electrostatic apparatus.



No. 831,916. PATENTED SEPT-25, 1906. M. WOODSOME. ELECTROSTATICAPPARATUS.

APPLICATION FILED AUG. 2, 1904.

I ATTORNEY.

MILLARD WOODSOME, or BOSTON, MASSACHUSETTS, ASSIGNOR, BY

MESNE ASSIGNMENTS,

TO HUFF ELECTROSTATIC SEPARATOR COMPANY, A CORPORATION -OF MAINE.

ELECTROSTATIC APPARATUS- Specification of Letters Patent. Applicationfiled August 2, I904. Serial No. 219,241.

Patented Sept. 25, 1906.

To all whom it may concern.-

Be it known that I, MILLARD WoonsoME, a citizen of the United States,and a resident of Boston, in the county of Suffolk and State ofMassachusetts, have invented new and useful Improvements inElectrostatic Apparatus, of which the following is a specification.

My invention relates to classifiers or graders for ores, metals, andminerals.

It relates particularly to a classifier in which the peculiar propertiesof static or hgh-potential electricity are made use of to e ect theseparation or classification and to the arrangement of the severalelements of a machine adapted to practically employ such electricity.

The object of this invention is to provide a device which shall rapidly,accurately, and economically produce a separation and classification ofthe various substances and values embraced in an ore or mineral or otherheterogeneous mixture where the constituents are of differingsusceptibility to the repellent effect of an electric charge.

To carry out this invention I have invented the machine whereof aconvenient and approved form is set forth and illustrated in theaccompanying drawing and s ecification.

The drawing shows two doub e machines, each consisting of two similardevices placed one above the other, the two similar airs of apparatusdischarging one of their 0 assified products into a common chute orreceptacle.

In the drawing, 1 is a hopper through which the crushed-ore 2 is fed ina finelyspread-out stream to an electrode 3, connected to a source ofstatic or high-potential electricity. Close to this highly-chargedelectrode 3 is placed another oppositely-charged electrode 4. Betweenthe two electrodes there is an adjustable fender or divider 5, made ofnon-conductin .material and servin both as a divider or the materialsrepe led from the electrodes and as a guide for the descent of thematerial arrested thereby.

To insure a concentrated and stron electric field, the electrode 4 ispreferab smaller than the electrode 3 and formed of a wire or rodinclosed in a y made can be highlyinsulating material, such as glass,micanite, &c. The electrode 4 is supported by an electrode-support 6,adjustably attached to the frame 7, as shown in one manner at 8. Theelectrode 4 is attached to an electric terminal of opposite polarity tothat of electrode 3. This electrode 4 can be dispensed with; but

its use increases the efiiciency of the apparathe common discharge-chuteof the two double machines. There may be a necessity for a more thoroughconcentration than is obtained by the ore passing over the electrode 3,and hence below the separators 5 and 10 there is provided a conduit 12for conveying the portion of the ore fallingbetween the fenders 5 and 10down to the electrode 3, where another concentration takes place andwhere 3*, 4 5 10, and 9 perform the same functions as are performedabove by 3, 4., 5, 10, and 9.

. The operation of the machine is as follows Assume an ore that it isdesired to classify into three graded products. The ore descending theho per 2 comes in contact with the rotating efectrode 3. Its conductiveportion becomes charged by contact with the electrode 3 and that part isthrown out over the separator 5, this action being assisted by theelectrode 4. This isolates one of the graded products of theclassification. A second constituent of the ore is less charged by theelectrode or in the short interval per haps not at all charged and fallsdown by gravity between the separators 5 and 10 into another receptacleor is passed on, if deslred, to the lower electrode 3 to be furtherconcentrated. This gives the second of the graded products of theclassification. The third or residue portion may be composed of amaterial so fine that it sticks to the elec-' trode 3 and is brushed offby the brush 9 of the ore.

into the receptacle to which separator leads, in the drawing shown asthe common tailings-receptacle.

When certain ores are submitted to the action of an electrostaticseparator, the finemesh portion, more commonly called slimes, is readilyrepelled, while in certain other ores they are not repelled to anyextent. Taking advantage of this fact, I can so construct and adjust mymachine that I can obtain the slimes product as a separate product fromthe relatively coarser particles In certain ores the slimes carry alarge percentage of the mineral values of the ores, while in certainother ores they carry a i very small percentage of such mineral values.

It therefore becomes advantageous to sepa rate or classify this slimesproduct from the coarser .mesh of the ores. In those ores in which theslimes product is repelled from the electrodes the slimes mineral isalso repelled,'and I obtain as a product the slimes mineral plus acertain percentage of the slimes of the gangue. In this class of oresthe slimes product is repelled from the electrode 3, and at thiselectrode very little of the coarser conductive particles are repelled.These coarser particles are repelled at the electrode 3 In the class ofores in which the slimes product is not repelled from the electrode Iget as a product a large percentage of the slimes of the gangue and avery small percentage of the slimes of the minerals. Of the coarser meshof the ores the mineral values or conductors are repelled from theelectrode as a high-grade mineral product. In ores where the slimes arerepelled from the electrode both the slimes and the coarser mineralparticles of the ore from a product that in most cases is applicable tosmelting and the slimes and coarser mineral values do not need to beseparated, or, if it is desirable, the slimes product that is repelledfrom the electrode, as 3, canbe collected as a separate product. Thiswould be advisable when the repelled mineral product is to be furtherpulverized, the slimes product being already mineral.

In ores where the slimes are not'repelled I have in many cases a productthat is applicable to amalgamation or cyaniding at the mine, while ofthe coarser meshes of this ore, the mineral values havin been expelled,the mineral values are available as a smelter product. I have thus bythe electrostatic separator classified the ore into a product fortreatment at the mine and a product forv shipment to the smelter. Aspecific ore applicable to this classification is an ore containingchlorids of silver, sulfids' of copper, and a porphyry gangue. Thecrushed ore is subjected to the electrostatic separator, and the sulfidsof copper with a proportion of the chlorids of silver are repelled fromthe electrode and is available as a smelter product.

The slimes of the porphyry gangue and the coarser mesh of the porphyrygangue are separated into two products containing chlorids of silver,and these two products are applicable to amalgamation at the mine. Asanother example, take an ore containing chlorids of silver and sulfidsof iron, gold, and a quartz gangue. The crushed ore is submitted to theelectrostatic separator, and the chlorid of silver in the form of aslimes product is separated by repulsion from the angue and. from thesulfids of iron. The s'uIfids of iron are separated by expulsion at thenext electrode from the quartz gangue and. are available as a smelterproduct. The quarts gangue is a worthless tailings product. The chloridsof silver are applicable to amalgamation at the mine.

The great value of the electrostatic classitying-separator resides inthe fact that with it I can separate from such ores as have beenmentioned above as examples and. from most ores in general therelatively fine mesh commonly called slimes, of the ores, either as arepelled product or as one of the tailings products. This is somethingthat has not hitherto been done profitably by any mechanical or electricprocess so far as I am informed.

Having thus fully described my invention, what I claim is x 1. In anelectrostatic separator, a pair of opposed electrodes, means to feedmaterial to the surface of one of said electrodes, a tender between thetwo electrodes, with its upper edge between the vertical tangent to theelectrode upon which the material is fed and the opposed electrode, asecond fender below the first electrode with its upper edge between theaforesaid vertical tangent, and said electrode.

2. In an electrostatic separator, a repelling-electrode and oppositeelectrode, means to feed material upon the repelling-electrode, a fenderwith its upper ed e between the vertical tangent to therepelling-electrode and the opposite electrode, a secondfender below therepelling-electrode with its upper edge inside of said vertical tangent,and a scraper in contact with the repelling-electrode above said secondfender.

3. In an electrostatic separator, the ,combination of a rotarycylindrical repellingelectrode, an opposed electrode, a fender with itsupper edge between the vertical plane tan cut to the rotary cylinder andthe opposed e ectrode, a second fender below the rotary electrode andbetween it and said ver tical tangent.

4. In an electrostatic separator, the combination of a rotar electrode,an oppose electrode, a fender with its upper edge between the verticalplane tangent to the rotary cylinder and opposed electrode, a secondfender below the rotary cylindrical rep'ellingelectrode and between itand said Vertical Signed by me at Boston, Massachusetts, tangent,l and gscrl'aper in coltactf Witl the this-10th day of June, 1904.

rotary e ectro e, t e upper e e o sai sec- 0nd fender being between saidvertical tanl MILLARD WOODSOME' gent and a vertical plane passingthrough the Witnesses:

line of contact of the scraper With the rotary ARTHUR F. RANDALL,

electrode. CHARLES D. WOODBERRY.

